Deciding that it would be best to check out what was causing the noises from above, you headed up the stairs, your arms carrying the girl with you. As you reached the top of the stairs, you see that the bridge consist of two railroad tracks running side by side over the city.
Looking down the track, you see a red knightmare, strangely missing one arm, riding down the tracks with two more purplish knightmares, similar to the ones you saw earlier, following closely behind, as if they were chasing the red one. The purplish knightmares were quickly catching up to the one in front, and just when it seemed like they would reach it, a train came barreling down the track, hitting and slowing down the two knightmares as the red one quickly leaped over the train. The train didn't stop the two knightmares for long, as one of the purple knightmares attempted to leap on the train.
Suddenly, before the purple knightmare reached the ground, two slash harkens fire out from a nearby building and hit the knightmare, destroying it completely. You couldn't see exactly what was in that building from your position, but the purple knightmare seemed to face whoever fired out the harkens only to receive a hail of bullets which crippled the knightmare's leg. Before the knightmare had a chance to counterattack, however; the crimson colored knightmare charged out, forcing the knightmare to fire out what looked like a rocket.... no, an ejection pod, which flew out in to the air for a while until air chutes popped out and the pod softly floated to the ground.
Turning back to the red knightmare, you saw that a couple of people came to meet the reddish knightmare. Although it was hard to make out from your position, it looked to be a fairly large group of elevens and they seemed to be carrying... guns.
The whole scene suddenly made sense now: the people in front of you are terrorist, elevens who oppose Britannia's rule over Japan. Watching the terrorist from your hiding place at the stairs, you see them talking to someone over the radio, though you are too far away to listen to what they are saying. Walking over to the sides of the train, one of the rebels open the container door and, to your amazement, reveals a vast collection of Knightmares stored in the train. You had no idea where the elevens had managed to obtain such a large collection Knightmares but a chance has just opened up for you.
You had no idea wether or not you have seen the last of Britannian soldiers that are looking for you, but if you could sneak in try to steal one of the knightmares then you use it to escape, but there was always a chance that you would get caught and the rebels would not treat a Britannian like you too nicely. Your second options could be to attempt to follow behind, and use the chaos of what looks to be an open up attack on the Britannian army by the rebels. Either way sounded risky, but it seemed much better then trying to get out on your own.